From the book

If you want a great site, you’ve got to test. After you’ve worked on a site for even a few weeks, you can’t see it freshly anymore. You know too much. The only way to find out if it really works is to watch other people try to use it.

Testing reminds you that not everyone thinks the way you do, knows what you know, and uses the Web the way you do.

I used to say that the best way to think about testing is that it’s like travel: a broadening experience. It reminds you how different—and the same—people are and gives you a fresh perspective on things.&sup1;

But I finally realized that testing is really more like having friends visiting from out of town. Inevitably, as you make the rounds of the local tourist sites with them, you see things about your hometown that you usually don’t notice because you’re so used to them. And at the same time, you realize that a lot of things that you take for granted aren’t obvious to everybody.

Testing one user is 100 percent better than testing none. Testing always works, and even the worst test with the wrong user will show you important things you can do to improve your site.

When I teach workshops, I make a point of always doing a live usability test at the beginning so that people can see that it’s very easy to do and it always produces valuable insights.

I ask for a volunteer to try to perform a task on a site belonging to one of the other attendees. These tests last less than fifteen minutes, but in that time the person whose site is being tested usually scribbles several pages of notes. And they always ask if they can have the recording of the test to show to their team back home. (One person told me that after his team saw the recording, they made one change to their site which they later calculated had resulted in $100,000 in savings.)

Testing one user early in the project is better than testing 50 near the end. Most people assume that testing needs to be a big deal. But if you make it into a big deal, you won’t do it early enough or often enough to get the most out of it. A simple test early—while you still have time to use what you learn from it—is almost always more valuable than an elaborate test later.

Part of the conventional wisdom about Web development is that it’s very easy to go in and make changes. The truth is, it’s often not that easy to make changes—especially major changes—to a site once it’s in use. Some percentage of users will resist almost any kind of change, and even apparently simple changes often turn out to have far-reaching effects. Any mistakes you can correct early in the process will save you trouble down the line.

1. As the Lean Startup folks would say, it gets you out of the building.